A viscoelastic surfactant (VES) for a self-diverting acid under high temperature has a structural formula shown as formula (I), wherein, n is saturated hydrocarbon with 2 to 8 carbon atoms; R.sub.1 is saturated or unsaturated hydrocarbon with 18 to 28 carbon atoms; R.sub.2 and R.sub.3 are independently methyl, ethyl or hydrogen, and R.sub.2 and R.sub.3 can be the same or different; and X.sup.− is any one of Cl.sup.−, Br.sup.−, CO.sub.3.sup.2−, SO.sub.4.sup.2−, HCOO.sup.− and CH.sub.3COO.sup.−. The method for preparing the surfactant includes subjecting a fatty acid and an organic amine to acid-amine condensation to obtain an intermediate. The intermediate reacts with a metal hydride to obtain a fatty amine. Then, an acid solution is used to protonate the fatty amine to obtain an ultra-long-chain viscoelastic cationic surfactant. The present invention also provides use of the surfactant as a thickener for a self-diverting acid.

A viscoelastic surfactant (VES) for a self-diverting acid under high temperature has a structural formula shown as formula (I), wherein, n is saturated hydrocarbon with 2 to 8 carbon atoms; R.sub.1 is saturated or unsaturated hydrocarbon with 18 to 28 carbon atoms; R.sub.2 and R.sub.3 are independently methyl, ethyl or hydrogen, and R.sub.2 and R.sub.3 can be the same or different; and X.sup.− is any one of Cl.sup.−, Br.sup.−, CO.sub.3.sup.2−, SO.sub.4.sup.2−, HCOO.sup.− and CH.sub.3COO.sup.−. The method for preparing the surfactant includes subjecting a fatty acid and an organic amine to acid-amine condensation to obtain an intermediate. The intermediate reacts with a metal hydride to obtain a fatty amine. Then, an acid solution is used to protonate the fatty amine to obtain an ultra-long-chain viscoelastic cationic surfactant. The present invention also provides use of the surfactant as a thickener for a self-diverting acid.

There is described a method of reducing polymer tar build-up in the production of methyl methacrylate and/or methacrylic acid by the acetone cyanohydrin process. In the method a stabiliser is contacted with the amide stage reaction medium. The stabiliser includes a hydrocarbon moiety capable of donating a labile hydrogen atom to a methacrylamide derivative capable of reaction with said labile hydrogen atom under the conditions in the said medium. The method herein is especially useful for the continuous production of methyl methacrylate and/or methacrylic acid.

There is described a method of reducing polymer tar build-up in the production of methyl methacrylate and/or methacrylic acid by the acetone cyanohydrin process. In the method a stabiliser is contacted with the amide stage reaction medium. The stabiliser includes a hydrocarbon moiety capable of donating a labile hydrogen atom to a methacrylamide derivative capable of reaction with said labile hydrogen atom under the conditions in the said medium. The method herein is especially useful for the continuous production of methyl methacrylate and/or methacrylic acid.

An adhesive composition having excellent adhesive properties and adhesiveness to a variety of plastics such as polypropylene, polyethylene, or a cycloolefin resin. The adhesive composition includes a polymer having a repeating unit derived from a polymerizable compound of the following formula (I):

##STR00001##

in which X.sup.1 and X.sup.2 each independently represent a C7 to C20 alkyl group or a C7 to C20 alkoxy group; n represents 0 or 1; Z.sup.1 and Z.sup.2 each independently represent a single bond or a C1 to C3 alkylene group; R each independently represents an organic group or a halogeno group; m1 and m2 each independently represent any integer of 0 to 4; and Y represents a polymerizable functional group.

An adhesive composition having excellent adhesive properties and adhesiveness to a variety of plastics such as polypropylene, polyethylene, or a cycloolefin resin. The adhesive composition includes a polymer having a repeating unit derived from a polymerizable compound of the following formula (I):

##STR00001##

in which X.sup.1 and X.sup.2 each independently represent a C7 to C20 alkyl group or a C7 to C20 alkoxy group; n represents 0 or 1; Z.sup.1 and Z.sup.2 each independently represent a single bond or a C1 to C3 alkylene group; R each independently represents an organic group or a halogeno group; m1 and m2 each independently represent any integer of 0 to 4; and Y represents a polymerizable functional group.

This invention relates to a method for inhibiting the agglomeration of gas hydrates, comprising the injection of an anti-agglomerant comprising a N,N-dialkyl-ammoniumalkyl fatty acid amide represented by the formula (I) ##STR00001##
wherein R.sup.1 is an alkyl or alkenyl group having from 7 to 21 carbon atoms, R.sup.2 and R.sup.3 are each independently an alkyl group containing 1 to 10 carbon atoms, or together form an optionally substituted ring having 5 to 10 ring atoms, wherein the ring may carry up to 3 substituents, R.sup.4 is hydrogen or an alkyl group having 1 to 6 carbon atoms, R.sup.5 is hydrogen or an optionally substituted hydrocarbyl group having 1 to 22 carbon atoms and A is an alkylene group having two or three carbon atoms,
into a fluid comprising gas, water and oil under conditions prone to the formation of gas hydrates,
wherein the N,N-dialkyl-ammoniumalkyl fatty acid amide represented by formula (I) is produced by the aminolysis of an ester of a fatty acid and a C.sub.1- to C.sub.4-alcohol with an N,N-dialkylamino alkyl amine and subsequent neutralization with a carboxylic acid.

This invention relates to a method for inhibiting the agglomeration of gas hydrates, comprising the injection of an anti-agglomerant comprising a N,N-dialkyl-ammoniumalkyl fatty acid amide represented by the formula (I) ##STR00001## wherein R.sup.1 is an alkyl or alkenyl group having from 7 to 21 carbon atoms, R.sup.2 and R.sup.3 are each independently an alkyl group containing 1 to 10 carbon atoms, or together form an optionally substituted ring having 5 to 10 ring atoms, wherein the ring may carry up to 3 substituents, R.sup.4 is hydrogen or an alkyl group having 1 to 6 carbon atoms, R.sup.5 is hydrogen or an optionally substituted hydrocarbyl group having 1 to 17 carbon atoms and A is an alkylene group having two or three carbon atoms, into a fluid comprising gas, water and oil under conditions prone to the formation of gas hydrates, wherein the N,N-dialkyl-ammoniumalkyl fatty acid amide represented by the formula (I) is produced by the condensation reaction of a fatty acid with an N,N-dialkylamino alkyl amine and subsequent neutralization with a carboxylic acid.

This invention relates to a method for inhibiting the agglomeration of gas hydrates, comprising the injection of an anti-agglomerant comprising a N,N-dialkyl-ammoniumalkyl fatty acid amide represented by the formula (I) ##STR00001## wherein R.sup.1 is an alkyl or alkenyl group having from 7 to 21 carbon atoms, R.sup.2 and R.sup.3 are each independently an alkyl group containing 1 to 10 carbon atoms, or together form an optionally substituted ring having 5 to 10 ring atoms, wherein the ring may carry up to 3 substituents, R.sup.4 is hydrogen or an alkyl group having 1 to 6 carbon atoms, R.sup.5 is hydrogen or an optionally substituted hydrocarbyl group having 1 to 17 carbon atoms and A is an alkylene group having two or three carbon atoms, into a fluid comprising gas, water and oil under conditions prone to the formation of gas hydrates, wherein the N,N-dialkyl-ammoniumalkyl fatty acid amide represented by the formula (I) is produced by the condensation reaction of a fatty acid with an N,N-dialkylamino alkyl amine and subsequent neutralization with a carboxylic acid.

Disclosed are a mild and efficient preparation method for an α-acyloxyenamide compound and a use thereof in the synthesis of an amide and a polypeptide. The α-acyloxyenamide compound is obtained by an addition reaction of a ynamide and a carboxylic acid in dichloromethane under conditions where the temperature is 0° C. to 50° C.; the produced α-acyloxyenamide compound can react with an amine compound to produce an amide or a polypeptide; the two reactions can be carried out step by step, and can also be carried out in one pot. According to the invention, the reaction conditions are mild and no metal catalyst is required; when the carboxylic acid, which has chirality on an alpha site of carboxyl, forms an amide bond or a peptide bond, no racemization occurs; and the operation is simple and the application range is wide.